Production of C.sub.6 -C.sub.9 aromatics is important to the chemical and petroleum industries. These aromatics improve the octane number of lead-free motor fuel. Dehydrocyclization is an attractive process for upgrading low octane refinery streams to high octane lead-free motor fuel blend stocks. It may also be used to increase the supply of aromatics for producing various petrochemical intermediates. For example, benzene and toluene are used in the manufacture of other aromatic compounds such as chlorobenzene, trinitrotoluene and styrene. These aromatics can be produced from paraffins and/or cycloparaffins by catalytic reforming at relatively high temperatures e.g., above about 950 F., in the presence of hydrogen and steam. A known process for the catalytic dehydrogenation and dehydrocyclization of various alkanes diluted with steam and in the absence of free oxygen is disclosed by Box, et al in U.S. Pat. No. 3,461,177 (1969). In U.S. Pat. No. 3,670,044 (1972) Drehman et al disclose that certain alkanes diluted with steam can be subjected to catalytic dehydrogenation in the presence of gaseous hydrogen or mixtures of gaseous hydrogen and gaseous oxygen.
The dehydrogenation and cyclization reactions which result in the formation of C.sub.6 to C.sub.9 aromatics are highly endothermic. Conventionally, the heat required to maintain the reaction temperature is supplied by steam mixed with the feed and by interstage heaters. Generally a high mole ratio of steam to hydrocarbon feed, e.g., about 10/1 to 15/1, is required to obtain high conversion rates and selectivity to aromatics. Since usually fuels are burned to supply the energy for generating steam, it is desirable to develop a process which requires relatively less steam, and therefore less combustion of additional fuel.